Refrigerating apparatus



Nov. 29, 1966 J.J. ocoNNELL ETAL 3,287,930

REFRIGERATING APPARATUS 4 Sheets-Sheet 1 Original Filed Feb. l0, 1964 Nov. 29, 1966 J. J. OCONNELL ETAL REFRIGERATING APPARATUS Original Filed Feb. l0, 1964 4 Sheets-Sheet 2 Nov. 29, 1966 .1.J. OCONNELL ETAL 3,287,930

REFRIGERATING APPARATUS 4 Sheets-Sheet 4 Original Filed Feb. lO, 1964 rNvENToRs l0/m J. U'GOnne/l Leona J. Mann The/'r Afforney Fig. 7

United States Patent O 3,287,930 REFRIGERATING APPARATUS John J. OConnell, and Leonard I. Mann, Dayton, Ghio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application Feb. 10, 1964, Ser. No. 343,736, now Patent No. 3,252,292, dated May 24, 1966. Divided and this application Sept. 13, 1965, Ser. No. 486,648 1 Claim. (Cl. 62-277) This application is a division of our copending application Serial No. 343,736, `filed February 10, 1964, now Patent No. 3,252,292.

This invention pertains to refrigerating apparatus and more particularly to a refrigerator having :below and above freezing compartments separately cooled by separate air circuits cooled by a single evaporator.

rl`he Igrowing popularity of frost f-ree refrigerator compartments makes it desirable to market a greater variety of sizes of refrigerators having this and other desirable features. It is therefore an object of this invention to p-rovide a large capacity, compact, economical, low cost refrigerator which is inexpensive to manufacture and maintain, having the desired below and above freezing temperatures in separate compartments which will no-t accumulate frost in any of the storage compartments.

It is another object of this invention to provide a compact, removable refrigerating syste-m and a convenient inexpensive ar-rangement including a removable wall section of minimum size for readily installing and removing such Va system in a foam insulated refrigerator cabinet.

It is another object of this invention to provide an improved compact, efficient air circulating system for a two-compartment refrigerator cabinet.

It is another object of this invention to provide a simple single compact evaporator in a two-compartment refrigerator which minimizes the obstruction to air flow due to frost accumulation on the evaporator surfaces.

It is another vobject of this invention t-o provide a well arrangement in a foam insulated refrigerator cabinet by which the thermosensitive ele-ment of the control system may be readily inserted and located in the desired place yand readily removed whenever desired.

It is another object of this invention to provide an improved arrangement for defrosting an evaporator and environ-mental parts subject to frosting.

These and other objects are attained in the form shown in the drawings in which the lower below freezing compartment is provided with a raised rear portion over the compressor and condenser above which there is mounted a single vertically finned evaporator having widely spaced fins at one end and closely spaced fins for the remainder thereof. An insulated vertical partition wall separates the evaporator from the below freezing compartment immediately in front of it. The below freezing compartment is cool-ed by air which is drawn under the bottom of the partition wall and upwardly through the closely finned portion of the evaporator and discharged back into the compartment by a propeller type fan located in an aperture in the partition wall. The rear insulated wall of the below freezing compartment is provided with an opening normally closed by a narrow removable section which is slightly higher than the height of the evaporator and slightly wider than the thickness thereof. The compressor and condenser mounted beneath the raised portion are connected by .snp-ply and return conduits which extend through the opening in the rear wall and connect to the opposite end of the evaporator through two looped Iportions located at the opposite ends of the evaporator. This arrangement provides sufficient flexibility in the connections that the evaporator can be readily inserted through this opening and mounted at the CII ice

back of -the below freezing compartment. It may likewise be readily removed along with the removal of the compressor, land the condenser for examination and repair in the event of any failure.

A duct extends diagonally upwardly from the zone imediately above the widely spaced iin portion and has a first discharge outlet behind the meat-keeping container in the lower right side, and a second discharge outlet in the top central `portion of the above freezing compartment. On the lower left side of the above freezing compartment is a centrifugal fan which discharges through an expanding duc-t diagonally downward t-o a discharge outlet located behind the lower por-tion of the widely spaced finned evaporator portion. A switch mounted in the top portion of the above freezing compartment has a thermosensitive element extending downwardly through a well or tube in the foam insulation extending to the top of .the below freezing compartment so as to make the switch responsive to the temperature of the Vair at the top of the below freezing compartment. The centrifugal fan loated in the lower left part of the above freezing compartment is cycled in response to the temperature of the adjustable tlhermostatic switch mounted in the top portion of the above freezing compartment, and having a thermosensitive element located above the second discharge outlet so `as to be responsive to the temperature of the above freezing compartment. A timer periodically defrosts both sections of Ithe evaporator through a serpentine electric heater lodged i-n the fins of the evaporator having a proportionately greater portion in heat transfer relation with the widely spaced tin porti-on of the evaporator Awhich accumulates the most frost. The drain surfaces as well as the partition wall are provided with heaters energized coincidentally with the energization of the defrost heater for melting any frost or ice accumulating on the drain surfaces or the partition wall. The drain is provided with a lremovable cover for easy cleaning and is provided with a simple removable trap in the machinery compartment.

Further objects and advantages of the present invention will be apparent from the following description, reference bein-g had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE l is a front view, with the doors removed, of a 2-compartment household refrigerator embodying one form of our invention;

FIGURE 2 is an irregular vertical section taken substantially along the lines 2 2 of FIGURE l;

FIGURE 3 is a fragmentary sectional view taken substantially along the lines 3-3 of FIGURE l;

FIGURE 4 is an enlarged sectional view corresponding to the bottom of FIGURE 3 showing the heaters for the drain surface and the partition wall;

FIGURE 5 is a sectional view taken along the lines 5 5 of FIGURES 1 and 2;

FIGURE 6 is a front view of the below freezing compartment showing the cycle evaporator in position for removal through the opening provided in the rear wall; and

FIGURE 7 is a wiring diagram.

Referring now more particularly to FIGURES l and 2, there is shown a foam insulated household refrigerator cabinet 20, having an upper above freezing compartment 22, and a lower below freezing compartment 24, beneath which is a machinery compartment 26 having separating the latter compartments a low front insulated wall portion 28 and a stepped up rear wall portion 30, which is raised substantially above the front portion 28 to provide adequate space beneath for the sealed motor compressor unit 32 and the sheet-type condenser 34. The rear insulated wall 36, behind the below freezing compartment 24, is provided with a narrow vertical removable portion 38 covered by a metal cover 40 beneath the lower edge of which extends the capillary tube supply conduit 42 connecting the condenser 34 with the single evaporator 44 and a suction conduit 46 connecting the outlet of the evaporator with the suction inlet of the compressor 32. On the left end of the evaporator 44 the conduits 42 and 46 are provided with a vertical loop portion 48 providing flexibility of the conduits 46 and 42 to permit removal of the evaporator 44 through the opening provided when the removable portions 38 and 40 are removed.

This removal is clearly illustrated in FIGURE 6. The entire refrigerating system may be removed by removing the compressor 32 and the condenser 34 through the opening in the back of the machinery compartment 26 along with the evaporator 34, so that the refrigerating System is kept intact and may be removed for examination or sent away for repair. The refrigerating system is readily inserted by inserting the right end through the opening provided by the removal of the section 38, and passing the entire evaporator through this opening and then placing it above the rear of the raised portion 30. The refrigerant conduits 42 and 46 extend from the condenser 34 and the compressor 32 through the opening at the bottom of the section 38 to the looped portion 48 and connecting respectively to the inlet connection 50 and to the top of a vertically mounted accumulator 52 having its bottom portion connected to the evaporator outlet 54. The evaporator 44 has horizontal serpentine tubing provided with widely spaced vertical lins 56 on the right side of the vertical partition wall 58 and a closely iinned section 60 on the left side of the vertical partition wall 58. An insulated partition wall 62 is provided in front of the evaporator 44 and substantially extends entirely across the rear of the below freezing compartment 24. It includes an insulating' sheet 64 which is faced with a metal sheet 66 having a bottom edge 68 turned rearwardly at an angle beneath the lower beveled bottom portion of the insulating sheet 64. Behind the upper portion of the sheet portion 64 is provided with a horizontal insulated structure 70 spaced above the evaporator 44 having vertical partition wall portions 71 and 73 extending downwardly to the opposite ends of the evaporator 44 andan intermediate vertical wall portion 76 extending downwardly to the partition wall 58. The insulating sheet 64 and the metal facing sheet 66 are terminated short of the step portion 40 in front of the closely spaced iin portion 60 to provide an air entrance 70 through which air from the compartment 24 enters the space beneath the closely finned part 60 of the evaporator 44. A propeller-type fan 72 is rotatably mounted` in an aperture 74 in the sheet 64 and the metal sheet 66 at a level higher than the evaporator 44 between the wall portion 71 and 76 for drawing the air from the compartment 24 beneath the bottom beveled edge 68 for drawing the air upwardly through the closely spaced iin portion 60 and discharging the air forwardly in the upper portion of the below freezing compartment 24. It is driven by an electric motor 69.

A fan scroll 78 located on the lower left-hand corner of the back wall of the above freezing compartment 22, surrounds a centrifugal fan 80 driven by an electric motor 82 for drawing air from the above freezing compartment, and discharging the air through an expanding shroud 84 to a duct 86 extending through the rear wall 36 diagonally downwardly to a discharge outlet 88 in the rear wall 36, behind the bottom of the widely spaced finned portion 56, of the evaporator 44. This air flows upwardly through the widely spaced iin portion 56 to the air entrance 90 above the evaporator 44. The entrance 90 leads to a second air duct 92 in the rear wall 36 which extends diagonally upwardly and has a small first air discharge opening 94 discharging through the rear wall v within the back wall of the cabinet to the upper centrally located discharge outlet 123 located a few inches below the top wall of the refrigerator cabinet. The fan is preferably located directly behind the high humidity container 98 on the left side of the above freezing compartment 22, directly above the insulating wall 121 which separates the below freezing compartment 24 from the above freezing compartment 22. The air at a temperature of about 35 F. flows through the above freezing compartment 22 and around the container 98 to keep this container at a suitable temperature such as 35 F. for the moist storage of fruits and vegetables. On the rear wall of the compartment 22 between the outlet 123 and the top wall 126 is a thermosensitive element or capillary tube which is operably connected to the adjustable thermostatic switch 127 mounted on the right side of the discharge outlet 123. This switch 127 is connected in series with the fan motor 82, as indicated in FIGURE 7, for the purpose of maintaining the temperature in the compartment 22 at about 35 F., and the temperature in the meat-keeping container 96 at a temperature of about 30 F.

On the opposite side of the upper discharge opening 123 is a second adjust-able thermostatic switch 129 which has a thermosensitive element extending down through a tube or wel-1 131 in the insulation of the rear wall 36 to a terminal point 133 mounted on the top Wall 121 of the below freezing compartment 24 as shown in FIGURES 1 and 2. This thermosensitive element is in the form of a capillary tube having a closed end in the portion 133 and connecting at its upper end to a iluid motor within the switch 129. An illustration of such a `switch is shown in Pat. No. 2,906,132 issued September 29, 1959.

For the purpose of defrosting the evaporator 44, there is provided a serpentine sheathed electric heater 135 having, as shown in FIGURE 6, one lower loop 137 extending across both the ywidely spaced ns 56 'and the closely spaced ns 60 and having two short upper loops 139 extending into heat transfer relation only with the widely spaced ns 56 so as to provide more heat for this portion of the evaporator since a greater amount of frost collects upon it. Upon the backside of the evaporator are provided several loops 141 of the heater 135 which extend acrossfboth the closely spaced ns 60 and the widely spaced tins 56. For the purpose of collecting the Water during defrosting, the raised portion 30 is provided with an inclined drain trough 143 extending downwardly from the left to the right to a point opposite the sump and drain 145 in the 1re-ar right corner. sump and drain is provided with a removable cover 147 for access to the sump and drain for cleaning purposes, and for shielding the drain from the circulating air. The drain is connected to tubing 149 extending through the machinery compartment 26 to a removable diagonal drain and seal member 151 having a normally closed end portion 153 which normally has a at looped shape at the end so as to prevent ow of air therethrough. It, however, will allow the ow of water into the collee-ting drain pan 155 located in the front part of the machinery compartment 26 where it is in the flow of air which is circulated by the condenser fan 157 driven by the fan motor 159. The drain 143 is provided with a drain heater 161 in the form of a loop extending along the bottom having a second portion 163 (see FIG. 7) extending to the drain 145, and having a third portion 165 extending laterally between the bottom edge 68 of This v the sheet metal face 66 and the -beveled bottom edge of the insulating sheet 64 of the dividing wall 62.

As illustrated in FIGURE 7, a timer motor 167 is connected across the supply conductors L-1 'and L-2 and `at intervals of once or twice a day operates the dual switches 169 and 171 from the position shown in FIG- URE 7 to a position in which the switch 171 is opened and the switch 169 is closed. When the switch 171 is opened, the fan motors 76, 72, and 159, as Well as the motor compressor unit 32, are de-energized. The closing of the switch 169 energizes the defrost heater 135 including the portions 137, 139, 'and 141. Connected in parallel with the defrost heater are the -two portions of the drain heater 134 and 163, and the heater 165 upon the bottom of the member 66. The drain heaters insure that any ice in the drainage system Will be melted before the defrost water melted from the evaporator 44 reaches the different parts of the draining system. The heater 165 assures that any frost or ice collecting upon the partition wall 62 will -be melted during the defrost period. The fan motors 78 and 82 may also be stopped Whenever the doors 173 and 175 are opened through the opening of the switches 177 and 179 which are operated respectively by the doors 173 and 175.

The motor compressor unit along with the fan 157 and its motor 159 and the condenser 34 may be removed through the rea-r opening of the machinery compartment 26. The evaporator 44 may be removed by removing the section 38 of insulation and th'e cover 40 and withdrawing the evaporator through the opening provided by this removal as illustrated in FIGURE 6 by moving the -left end of the evaporator `44 rst through the opening and then withdrawing the remainder through the opening until it is free of the cabinets. The refrigerating system is capable of maintaining the compartment 24 at temperatures between |6 and 12 F. Norm-al operation is 0 F. While the above freezing compartment 22 is capable of maintaining a temperature of about 35 F. therein, with the exception of the meat-keeping container which is maintained -at about 30 F. The timer motor 167 provides defrost periods once or twice a day automatically without any attention. The foam insulation is suiiiciently eficient that only thin insulated walls are required. Theuse of -a single finned evaporator to cool both compartments makes the cost of manufacture relatively low, while the arrangement of completely separate air circulating systems between the two compartments and the two sections of the evaporator provide desirable temperature and humidity conditions in both compartments at a relatively low cost. The use of the diagonal duct arrangements makes the arrangement compact and minimizes the thickness required for the rear wall.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

A refrigerator. including insulating means enclosing a compartment, said compartment having a raised bottom wall portion extending across the rear of said compartment, means forming a machine compartment beneath said compartment having a portion of increased height beneath said raised bottom wall portion, a refrigerant liquefying lmeans having `a compressor with a major portion ylocated in said machinery compartment beneath said raised bottom Wall portion, a refrigerant evaporating means supported in said compartment above said raised bottom lwall portion, a partition wall extending upwardly from said raised bottom wall portion shielding the remainder of said compartment from said evaporating means, and means operatively connecting said evaporating and liquefying means, said raised bottom wall portion having a drain sump and a drain outlet connection extending from said sump through said wall portion, a drain disposer in said machinery compartment, and a drain conduit extending from said drain outlet connection to said drain disposer, said sump being provided with a 4removable cover for keeping cold air and foreign objects away from said sump Which is removable to provide access for cleaning said sump and said drain outlet connection.

References Cited by the Examiner UNITED STATES PATENTS 2,576,665 11/1951 BiXler.

2,912,834 11/1959 Mann 62-291 X 2,959,936 11/1960 Mann etal 6'2-285 X 3,004,401 10/1961 Mann et al 62-419 X 3,111,818 11/1963 Dolan et al. 62.-419 3,151,472 10/1964 Harle et al 62-419 X LLOYD L. KING, Primary Examiner. 

